[KAT500] Tuning

[W0JFR]

I don't think I understand how the tuning works with the KAT500. I have
a K3, KPA500, and the two 15-pin cables (K3 to KAT, and KAT to KPA).

I set my K3 Tune Power to 25w. I thought when I press tune on the K3,
the KAT500 should tune, and it shouldn't key the Amp; however, when I do
this, I continue to get around 500w from the Amp.

Could someone please explain how this is supposed to work?
Thanks,
   - 73, John, N0TA
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[Iain MacDonnell - N6ML-2]

On Sat, Dec 8, 2012 at 6:07 PM, John Reilly <[hidden email]> wrote:
> I don't think I understand how the tuning works with the KAT500. I have a
> K3, KPA500, and the two 15-pin cables (K3 to KAT, and KAT to KPA).
>
> I set my K3 Tune Power to 25w. I thought when I press tune on the K3, the
> KAT500 should tune, and it shouldn't key the Amp; however, when I do this, I
> continue to get around 500w from the Amp.
>
> Could someone please explain how this is supposed to work?

When you invoke the K3's TUNE function (hold the XMIT button), the K3
will make a 25W key-down signal. Nothing more fancy than that happens
at the K3.

If the KAT500 detects VSWR higher than the configured auto-tune
threshold, it will inhibit keying to the amp, and attempt to tune
(from memory first, then a full search if no suitable memory is
available). If the KAT500 does not detect VSWR higher than the
threshold, it will not inhibit keying, nor attempt any tune function.

Are you seeing high VSWR when you invoke the K3's TUNE function?

73,

    ~iain / N6ML
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[Eric Swartz - WA6HHQ]

The KAT500 will only initiate a tune based on SWR being above a threshold when it is in auto mode. Its manual mode requires a press of the tune button on the ATU first, followed by RF from the K3, for it to tune.

73,

Eric
www.elecraft.com
_..._

On Dec 8, 2012, at 6:32 PM, iain macdonnell - N6ML <[hidden email]> wrote:

> On Sat, Dec 8, 2012 at 6:07 PM, John Reilly <[hidden email]> wrote:
>> I don't think I understand how the tuning works with the KAT500. I have a
>> K3, KPA500, and the two 15-pin cables (K3 to KAT, and KAT to KPA).
>>
>> I set my K3 Tune Power to 25w. I thought when I press tune on the K3, the
>> KAT500 should tune, and it shouldn't key the Amp; however, when I do this, I
>> continue to get around 500w from the Amp.
>>
>> Could someone please explain how this is supposed to work?
>
> When you invoke the K3's TUNE function (hold the XMIT button), the K3
> will make a 25W key-down signal. Nothing more fancy than that happens
> at the K3.
>
> If the KAT500 detects VSWR higher than the configured auto-tune
> threshold, it will inhibit keying to the amp, and attempt to tune
> (from memory first, then a full search if no suitable memory is
> available). If the KAT500 does not detect VSWR higher than the
> threshold, it will not inhibit keying, nor attempt any tune function.
>
> Are you seeing high VSWR when you invoke the K3's TUNE function?
>
> 73,
>    ~iain / N6ML

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[ab2tc]

Hi,

Wouldn't all this work much better if the K3 did not key the amp when invoking the tune function? I don't have the KPA500 (yet) but the bypass function is not an option for me since my KAT500 is located remotely at the antenna site. This is working fabulously now that it has learned my frequencies. I am currently trying to raise 8P2K in the contest from the bedroom with my IC7200 to go transceiver. I can control the tuner from anywhere I can reach with my wireless or wired network. Awsome and this will greatly improve my summer operations from the rear deck. It was always a pain to have to run down to the basement to change antennas.

AB2TC - Knut

Iain MacDonnell - N6ML-2 wrote

On Sat, Dec 8, 2012 at 6:07 PM, John Reilly <[hidden email]> wrote:
> I don't think I understand how the tuning works with the KAT500. I have a
> K3, KPA500, and the two 15-pin cables (K3 to KAT, and KAT to KPA).
>
> I set my K3 Tune Power to 25w. I thought when I press tune on the K3, the
> KAT500 should tune, and it shouldn't key the Amp; however, when I do this, I
> continue to get around 500w from the Amp.
>
> Could someone please explain how this is supposed to work?

When you invoke the K3's TUNE function (hold the XMIT button), the K3
will make a 25W key-down signal. Nothing more fancy than that happens
at the K3.
<snip>

[ke9uw]

I don't think you quite got what he meant. There is some confusion as to whether the KEY OUT line is active when the TUNE button is pushed on the K3.
Sorry if I got it wrong, but some folks think that it would be advantageous if there were no key line output when pushing TUNE on the K3. Their issue is that the KAT is too slow in breaking the key line when tuning to safely not key the (whatever brand) amplifier.
We do know that there is firmware in the works for the KPA500 to have it not fault so quickly when it gets keyed at the beginning of a tune before the KAT500 drops the KEY LINE.
The simple solution is to put the amp in standby, or push tune on the KAT first, and then tune on the K3. I take it if you push tune first on the KAT, then it will open the key line first so that the subsequent pushing of tune on the K3 won't key the amp.

Chuck, KE9UW
Lionel Trains, TCA, LCCA, LRRC
aka Jack, BMW Motorcycles BMWMOA #224

________________________________________
From: [hidden email] [[hidden email]] on behalf of Eric Swartz WA6HHQ - Elecraft [[hidden email]]
Sent: Sunday, December 09, 2012 1:34 AM
To: iain macdonnell - N6ML
Cc: John Reilly; [hidden email]
Subject: Re: [Elecraft] [KAT500] Tuning

The KAT500 will only initiate a tune based on SWR being above a threshold when it is in auto mode. Its manual mode requires a press of the tune button on the ATU first, followed by RF from the K3, for it to tune.

73,

Eric
www.elecraft.com
_..._

On Dec 8, 2012, at 6:32 PM, iain macdonnell - N6ML <[hidden email]> wrote:

> On Sat, Dec 8, 2012 at 6:07 PM, John Reilly <[hidden email]> wrote:
>> I don't think I understand how the tuning works with the KAT500. I have a
>> K3, KPA500, and the two 15-pin cables (K3 to KAT, and KAT to KPA).
>>
>> I set my K3 Tune Power to 25w. I thought when I press tune on the K3, the
>> KAT500 should tune, and it shouldn't key the Amp; however, when I do this, I
>> continue to get around 500w from the Amp.
>>
>> Could someone please explain how this is supposed to work?
>
> When you invoke the K3's TUNE function (hold the XMIT button), the K3
> will make a 25W key-down signal. Nothing more fancy than that happens
> at the K3.
>
> If the KAT500 detects VSWR higher than the configured auto-tune
> threshold, it will inhibit keying to the amp, and attempt to tune
> (from memory first, then a full search if no suitable memory is
> available). If the KAT500 does not detect VSWR higher than the
> threshold, it will not inhibit keying, nor attempt any tune function.
>
> Are you seeing high VSWR when you invoke the K3's TUNE function?
>
> 73,
>    ~iain / N6ML

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[ab2tc]

Hi,

Pressing TUNE first will indeed open the Amp key, at least that's what the utility is telling me. See here:

http://ab2tc.getmyip.com/tune_without_power.png

Not sure what the "attenuator" checkbox means.

AB2TC - Knut

ke9uw wrote

I don't think you quite got what he meant. There is some confusion as to whether the KEY OUT line is active when the TUNE button is pushed on the K3.
Sorry if I got it wrong, but some folks think that it would be advantageous if there were no key line output when pushing TUNE on the K3. Their issue is that the KAT is too slow in breaking the key line when tuning to safely not key the (whatever brand) amplifier.
We do know that there is firmware in the works for the KPA500 to have it not fault so quickly when it gets keyed at the beginning of a tune before the KAT500 drops the KEY LINE.
The simple solution is to put the amp in standby, or push tune on the KAT first, and then tune on the K3. I take it if you push tune first on the KAT, then it will open the key line first so that the subsequent pushing of tune on the K3 won't key the amp.

Chuck, KE9UW
Lionel Trains, TCA, LCCA, LRRC
aka Jack, BMW Motorcycles BMWMOA #224

<snip>

[Igor Sokolov-2]

> The simple solution is to put the amp in standby, or push tune on the KAT
> first, and then tune on the K3. I take it if you push tune first on the
> KAT, then it will open the key line first so that the subsequent pushing
> of tune on the K3 won't key the amp.
>
> Chuck, KE9UW
> Lionel Trains, TCA, LCCA, LRRC
> aka Jack, BMW Motorcycles BMWMOA #224

This simple solution may work for tune but what about the following
situation:
Band 160m.
1810 kHz SWR = 1.5
1870kHz SWR = 6
KAT 500 was previously trained and remembers settings for both frequencies.
set up - K3+ KPA500 or any othrer combo capable of full break in
S&P in the contest, assisted. Click on 1810 spot and work station. Then
click on 1870 and start to send in full break in mode. TXD on the radio is 8
ms. T/R switching time of KPA500 is about the same or less. So far no
problems. But now KAT500 needs to switch to 1870 setting. M/B timing of the
relays used in KAT500 is 15 ms at best. So we have at least 7 ms of hot
switching relays in KAT500 and possibly KPA500 switching to fault (or both).

73, Igor UA9CDC

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